We conducted a study to investigate effects of bilingualism on nonverbal and verbal cognitive performance. Here we report on the results from the first part of our study, in which 26 middle-aged (MA 46) and 26 elderly (MA 73.2) early bilingual speakers of Dutch and Frisian performed a verbal fluency test, a task switching test and a working memory (WM) test. In an analysis focusing on between- and within-group differences, we found that the age-groups differed significantly in the task switching and WM tests and in the category switching component of the verbal fluency task. With regard to other factors, we found that the higher the degree of balance between participants&#8217; languages, the smaller their costs for switching between tasks.